Annoying Calls from *********** Staff

I am incessantly bombarded by their annoying calls every week, and their modus operandi seems to be either dead silence or abrupt hang-ups. On the rare occasions when they bother to utter a word, it's to inquire about someone I've never heard of and demand my personal details. Despite my futile attempts to communicate with their inept staff and explicitly instruct them to remove me from their system, my phone continues to ring relentlessly every weekday. It's a relentless parade of incompetence and disregard for basic courtesy.